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From: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [RFC PATCH 4/8] powerpc/64s: put io_sync bit into r14
Date: Fri, 22 Dec 2017 13:08:54 -0200	[thread overview]
Message-ID: <87a7ya6bqx.fsf@linux.vnet.ibm.com> (raw)
In-Reply-To: <20171220145206.12234-5-npiggin@gmail.com>


Hello Nicholas,

Just a small comment about syntax. I'm afraid I can't comment much about
the substance of the patch.

Nicholas Piggin <npiggin@gmail.com> writes:
> diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h
> index b9ebc3085fb7..182bb9304c79 100644
> --- a/arch/powerpc/include/asm/spinlock.h
> +++ b/arch/powerpc/include/asm/spinlock.h
> @@ -40,16 +40,9 @@
>  #endif
>
>  #if defined(CONFIG_PPC64) && defined(CONFIG_SMP)
> -#define CLEAR_IO_SYNC	(get_paca()->io_sync = 0)
> -#define SYNC_IO		do {						\
> -				if (unlikely(get_paca()->io_sync)) {	\
> -					mb();				\
> -					get_paca()->io_sync = 0;	\
> -				}					\
> -			} while (0)
> +#define CLEAR_IO_SYNC	do { r14_clear_bits(R14_BIT_IO_SYNC); } while(0)

Is there a reason for the do { } while(0) idiom here? If
r14_clear_bits() is an inline function, isn't it a single statement
already?

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

  reply	other threads:[~2017-12-22 15:09 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-20 14:51 [RFC PATCH 0/8] use r14 for a per-cpu kernel register Nicholas Piggin
2017-12-20 14:51 ` [RFC PATCH 1/8] powerpc/64s: stop using r14 register Nicholas Piggin
2017-12-20 14:52 ` [RFC PATCH 2/8] powerpc/64s: poison r14 register while in kernel Nicholas Piggin
2017-12-20 14:52 ` [RFC PATCH 3/8] powerpc/64s: put the per-cpu data_offset in r14 Nicholas Piggin
2017-12-20 17:53   ` Gabriel Paubert
2017-12-22 13:50     ` Nicholas Piggin
2017-12-20 14:52 ` [RFC PATCH 4/8] powerpc/64s: put io_sync bit into r14 Nicholas Piggin
2017-12-22 15:08   ` Thiago Jung Bauermann [this message]
2017-12-20 14:52 ` [RFC PATCH 5/8] powerpc/64s: put work_pending " Nicholas Piggin
2017-12-20 14:52 ` [RFC PATCH 6/8] powerpc/64s: put irq_soft_mask bits " Nicholas Piggin
2017-12-20 14:52 ` [RFC PATCH 7/8] powerpc/64s: put irq_soft_mask and irq_happened " Nicholas Piggin
2017-12-20 14:52 ` [RFC PATCH 8/8] powerpc/64s: inline local_irq_enable/restore Nicholas Piggin

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